Tonga Time (TOT) is 13 hours ahead of Coordinated Universal Time (UTC). This time zone is in use during standard time in: Pacific.
See full time zone map
Summer Time & DST
Some places observe daylight saving time/summer time during the summer, and therefore use TOST (Tonga Summer Time) in the summer.
Where and When is TOT Observed?
Pacific countries using TOT in the winter and TOST in the summer:
Other Time Zones in UTC +13
Some time zones exist that have the same offset as TOT, but can be found under a different name: